Brown pancetta in a large skillet over medium-high heat for 2 or 3 minutes, stirring occasionally. Add sausage to the same skillet and brown, breaking it up into small bite-sized chunks with a spatula while it cooks. Remove from heat and carefully drain excess fat from pan. Transfer pancetta and sausage to a 5 or 6-quart slow cooker crock.
Puree one can of cannellini beans (undrained) in a blender or food processor. Drain and rinse the other can of cannellini beans and add the puree and whole beans to slow cooker crock.
Add 6 cups chicken stock, red pepper flakes, chopped onion, potatoes, and Parmesan cheese rind to crock and stir to combine. Season with salt and black pepper, to taste.
Cover and cook on high for 3-4 hours or low for 6-7.
Place the half-and-half in a glass bowl. Add a little bit of the hot liquid from the soup to the half and half, to temper the half and half. Mix the tempered half and half into the soup.
Finish by adding the kale, freshly grated Parmesan cheese and remaining chicken stock, if necessary, to achieve the desired consistency.
Stir to combine and allow 5-10 minutes for kale to soften before serving.